Why Do High-Power Radar Systems Typically Require a Dual-Junction Circulator?

High-power radar systems typically use a dual-junction circulator because it provides greater isolation and better protection than a single-junction circulator.

Radar systems often use the same antenna for transmitting signals and receiving echoes. During transmission, the circulator directs high-power RF energy from the transmitter to the antenna. It then routes the weak reflected signals from the antenna to the receiver. The dual-junction design offers additional isolation, helping suppress reflected power caused by antenna mismatch, changing environmental conditions, or high VSWR.

The main benefits of a dual-junction circulator include:

• Higher isolation between the transmitter and receiver
• Better protection for the power amplifier and sensitive receiver front end
• Reduced transmitter leakage into the receiving channel
• Improved weak-target detection performance
• Greater reliability under high peak-power and high-VSWR conditions

A dual-junction circulator may have a larger footprint, higher cost, and slightly greater insertion loss than a single-junction device. Therefore, engineers should consider operating frequency, peak and average power, isolation, insertion loss, VSWR, pulse width, duty cycle, and thermal requirements during selection.

For high-power radar systems that share one antenna between transmitting and receiving, a dual-junction circulator is generally the more reliable choice.